Compressed air gun



Sept. 28, 1948. w. s. WELLS coMPREssEn AIRDGUN Filed Sept. 25, 1941 A TTOENEX Sept. 28, V1948. w. s. lwr:| s

l COMPRESSED AIR GUN 2 Sheets-Sheet 2 Filed Sept. 23, 1941 INVENTOR. v w/LL/AM s. WEL/ s BY v A T TOE NE Y Patented Sept. 28, 194g COMPRESSED AIR GUN William S. Wells, Palo Alto, Calif., assigner to Paul S. Lnforth, San Francisco, Calif. v

Application September 23, 1941, Serial No. 411,989

My invention relates to guns, and more particularly to guns powered by air under compression.

Among the objects of my invention are to provide a novel and improved air gun which is selfloading,

. Additional objects ci my invention will be broughtout in the following description of the same' taken in conjunction with the accompanying drawings wherein- Figure l is a side elevational view of a pistol embodying my invention,

Figure 2 is a longitudinal section through the pistol of Figure 1, in condition for firing,

Figure 3 is a view similar to Figure 2, illustrating the mode of operation of the gun mechanism in preparing the same for firing,

Figure 4. is a section inthe plane 4-4 of Figllle 2,3,

Figure `5 isa section in the plane 5-5 of Figure .3,

. Figures 6 and 6a are comparative views, magnified in part and depicting the features and manner of functioning of my improved piston,

yligure 7 isa fragmentary view of the pump mechanism, depicting an important feature thereof inthe operation of such pump,

vFigure 8 is a fragmentary View in sectionI through the barrel -oi the gun, illustrating an improved restraining device for holding the shot to firing position. l l

o My invention, for purposes of description, is shown embodied in an air gun of the pistoltype, for which itis particularly adaptable, though it is tobe understood that the features thereof are justas applicable to air guns of the rie type,

while. certain of thefeatures yinvolved in the` pumpare of general utility and, accordingly, are

not necessarily limited in their application to air guns. l

Referring to the drawings for a complete description of my invention, the pistol illustratedcompris'es a gunbarrel to the underside of which is afxed the cylinder I3 of a pump forv compressing theair employed as the source of power i'nthe gun. This cylinder carries a trough or'channel member I5 to the underside thereof,

this channel-member extending a substantial dois-V tance to therear of the cylinder, and to this extended portion, the handle |.1 of the pistol is attached. Y y

'Ifhe gun barrel is provided with a sight |9"at themuzzle endv'thereof, while the rear or breech y end cf the barrel is `provided with .a groove 2| for the receptionfof a plurality of shot 23. Thel 5 Claims. (Cl. 124-43) rear end of the groove is connected by a well 25, to the bore 21 of thev barrel at a point to the rear of the firngpositiony 29 of a shot in said barrel. The bore of the barrel extends throughout the entire'barrel and is adapted to slidably receive a breech 'pin 3| through the breech end thereof.

The pump cylinder |3 is of substantial diameter and provided with an end wall 33 at the breech end thereof, while at the other end, it is open. The cylinder opens through its end wall 33, into a small valve chamber 35 which is connected by a discharge channel 31 to the firing position of a shot in the barrel. A valve 39 is disposed in lthis valve chamber and is possessed of a valve stein 4| which extends to the rear, through a rear Wall extension 43 of the valve chamber. On its exposed end, it carries a spring 45 which is maintained under compression by a nut 41 threaded to the end of the valve stem. This arrangementnormally holds the valve to its valve seat in the valve chamber.

The rear wall extension 43 of the valve chamber carries a U-shaped yoke 49 which extends to the rear ofthe breech of the gun, and between the legs of .this yoke, are pivotally supported a pair o f levers. i f

One of these levers 5| is provided with a forked end 53 which straddles a section of reduced diameter in the protruding end of the breech pin 3 I, and is spring biased in the direction of urging the pin into the gun barrel, with the front end of the pin terminating approximately at the ring position' ofA a shot in the barrel. The spring 55 for biasing this lever is preferably of the coil spring type, encircling the pivot shaft of the lever, with `one end of the spring bearing against the lever, While the other end is hooked over an upright or bracket 51 aixed to the crotch of the yoke. To the lower end of the lever, there is pivotally connected a control arm or link 59 which extends in slidable relationship along the undersurface of the pump cylinder, and at the open end of the cylinder, the free end 6| of this ,control arm is turned upwardly.

The other lever 63 enables control of the valve 39 from a trigger 65. To realize such control, one end of the lever' bears against the exposed end of the valvestem, while the other end is connected to a link 61 connectedto or forming a part of the trigger and slidably supported in the channel I5. A front extension 69 of this connecting arm is turned upwardly to provide a slidable support for the armor link 59 connected to the breech pin lever.

The pump, in addition to the cylinder I3 already described, includes a piston 'H reciprocally mounted. in the cylinder, and a piston rod 'I3 connected to the piston. The piston is disposed with its work-surface facing the cylinder and Wall 33, While the piston rod Which is pivotally connected to the piston, extends a substantial distance beyond the open end of the cylinder.

At the'niu'zzleeridof the gnfbarrelg I pijovide a dependingilug 15, to Whiclrisf-pivdtallyconnected one end of a pump lever 71 to be employed in the operation of the pump. This lever, as shown in Figure 2, is shaped to provide a portion 'i9 extending along the guh yl'ca'jriel to the pump cylinder, and anotherf-.portionl at substantially right angles thereto, extending across the open end of thecylinder and terminating in a trigger guard T83vvhichr serves' 'the added purpose of a hand grip to facilitate inanipulation of the lever. v

The protruding end ci thespiston 4rod is pivotn ally secured to 'that vportion T9' of the levrrunning along vthe g un`barrel,ild at a 'point close to Vthe fulc'ruin of the lever. Thisprtidn of the lever is of ch 'nnel construction to r'eceive the pistn rod' and' enable the lever to snugly up against the gun barrel vv'hlnin'itsI closed psition as indicated in Figure 2. e

In the pump ass'embly.'A thus 0far' described, the line of dead center Vconnects thepi'vote'nd of thel pistn rffd' andthe' f ulc Km pht fof the pump lever, v`When the" `1s lofU substantialwdiarnet'er, theline, `of ad centerv lieat a 's'uiiicient angle vtothe gun barrel, "so that 'the 'point of connectiori of the rod t the lver'vvill travel .just slightly beyond deadc riterwvvh the-piston reaches'the en'dfo'f itscoiiiiressin'stroke. Under theeiect of the'lir, then "under compression, the'piston" i's"autoinatically 'locked 'under Vcmp'ressin. l

tiratori the ecinpress'ionstrok, magneten white urged to Withinv a -fraction Voi {an-inch of 4the eildvvall ofthe cyli'iider, vvhile on the intakestroke of lthel p`\uI`np, th;af/t is- When vthe pump: handle sfsvv'uhg outwardly/to its maximum extent, as is'determine'd by thepis'toriV rod s-trilging against the lov/ erv edge of -thelugl (Figure'), the piston vvvillbe partially withdravvnfrom the open v4end ofwthegcylinder. j' By such Withdrawal, thepis'ton,l it will be noted, lis cfausedftoengage the turned upjend-Bl of thearm gand carrythe samealong with it. ,Thishastheeifect-of With'- drawing the breech: pin adistancesuicient rto exposethelcore ,2l of the barrel, to thewellfan'd'A permitlof theentranceof a shotfirom the-'groove El." KYUponrestoration -of the pump lever-to its closedposition, tlreair cQnnedin-"t-he cylinder will becompressed. while at thesametimeyfthe iiring pin will beA :permittedvtomove 'forward `to 6 additional features#` of considerableimportance, J55` and -in the further discussion of my invention, these `features vvvill lbe stressed.

The particular :pump #described -i'sc '0f :atype knovvn asiasingle strokexpump; -In apumpdf this type, compression is real-ized-byonecompression f common, wherever they have been used, it liasfE been the practice to so design them as to provide a pump with a piston of small diameter and long stroke. The reasons for this are, firstly, that the sealing of a piston of small diameter is more easily realized, and, secondly, the friction offered by pistons of the prior art, which invariably lemploy expansible cups of rubber or leather, is soy great that a piston of substantial diameter would reduire considerable'expencliture' of power? to reciprocate the Same, even on' the intake 'stroke Such piston, to be effective, must eXert considerable 'lateral pressure against the cylinder wall when assembled therein, and the friction increases considerably above that in response to the lateral "spreading force of the air as it is compressed. 'Iherefore, in' order to realize high compression with a pump o-f this kind, it has been practically necessary, as previously indicated, to design such pumpsvvith small pistons and With long strokes. 1 have developed a piston having such superior sealing qualities and such a low coeiicientfof kfriction that the factorsy Whichl previouslyrha'd ftdbe considered in the design of pumps of this character, are nolonger.aflimitation on'ftheirl/desifg'n.

"Byconstructing a; pump'of substantialrdiameter, it is possible to compress a large volume 'of air into an exceedingly smallspacejwithwbutta vlery 'short stroke' of the piston. Therefore; the pump Vcylinder vmay be designed to havev a" relatively short longitudinal dimension, r'- and 'a "thishas the very material advantage of enabllnglthe application of a pump of thesingle stroketypexo a pistol, which by its very nature Ais 'of-:arelat'lvly short longitudinal dimension, whereas-ali pump adapted thereto.-

My improved-'piston ll, 'whichfienalcle'smeto accomplish such' a radical :design in :this "type v'of pump, comprises a cup-shaped element 85 #of metal" orlthe like,l having a cylindrical surface closely but not tightly fitting the interior offthe pump" fcylind'el;` and afcentral` perforated lug l"81 towhich the piston rod 13 'maybe pivotally-'cona heated. Theout'er circulant-ace of this-'element has a short threaddstud y39 extending centrally therefrdm.

Mounted on this studfis af'disk l9i"of'rubberlilce'in'aterial held iri-compressionagainst thev face offth'c'up-sh'aped element 85 by -a"meta1 z'editipression disk93 threaded tothe stud."'"The"rub ber-like -material is preferably of art'c'ial rubber 'c'n'efcrni of suchy `material being' "known under trade naine 'o'imKoroseaP 'vvhiclfis basicall formedifrom 'ari acetylene lderivativeknown u ynler o'f'one'of thevinylhalldesflhismatenait has 'fan uexc@eeingly vrow coefficient-softneubn and ressentie-uy yimaffectedby -oiisfor :lubricanas:- -frhe fradiusoftne idisk -91 of-this materia-1 is greater than=`thato`f the compression* ""dislr.'v 93 0 by an amount substantially equ'al to the thicknessk of'fthe 'compression disk; to formal mais-t; setlist whenthelpiston is 'assembled in" the cylihderjthe rim twill bef-forcedovery betweenthemerpheral ri'ni ofthe compression disk 93v andtnecylmuer -wau Awhere it 'will Vfit' snugly but'nottightly." "Underithej Qircum'staneesthe edge ofthe rubber-'like disk"'wilrliefsupstantiallyflush wiurthe wcrkz'face lof tnepiston. The piston ijs thusoapableofipractleally I free *movement j inJ the' eylinder'ln' the "ab- 7 "1 sence of' under confinement therein.

Such freedom of movement is enhanced'i'by preferably vbeve'li'rl'g faflong that circumferential edge 195. or the fdisk 93; 'bearing Lagainsttheiisl: 9 t; so that-When the 'disk A"SI-ly 'is' placed* under com;

aecomo,

apparent that during the initial portion of a compression stroke, such.y slidingk of the rim 94 results in the exposed edge of the turned lover rim being withdrawn from adjacent the work surface of the piston, thereby precluding the air under compression lfrom exerting any lateral pressure againstV this rim in the direction of the cylinder The pressure of the compressed air, under the above circumstances, must, therefore, be directed exclusively in a longitudinal direction causing the rim 94 to swell vand tightly pack the space between the compression disk 93V and cylinder wall, and wedge itself under increasing compression, intosuch clearance space as may exist between the cup-shaped element 85 and the cylinder wall, wherebyto effectively seal the piston against leakage` of air thereby. This manner of sealing is clearly illustrated in comparative Fig- -ures 6 and 6a of the drawings.

With a construction of this character and operating in the manner described, it will be apparent that thepiston maybe designed so as to normally move in the cylinder with considerable freedom, for any play which may normally be present will be effectively overcome by the compression of the air in the pump, working against the exposed edge of rim 94 of the sealing disk. Upon release of compressionjas when the gun is fired, the rim'94 is free to resume its original condition,` whereby the piston is again freely movable for subsequent pump operation. v

In conjunction with this improved piston, I employ a piston rod so designed as to function in perfect cooperation with the rest of the pump in realizing additional advantages .of considerable importance in the operation of such pump, and. more particularly in its effect upon the firing characteristics of the gun.

As was previously pointed out, the construction of a cylinder of large diameter permits of the compression of a large volume of air into a .space having an exceedingly small longitudinal dimension, with but a short stroke of the plston. In my improved gun, the distance between the piston and the end wall of the cylinder upon the completion of the compression stroke, may be of the order of a hundredth of an inch. If upon release of the air from the cylinder, which release occurs at the moment of firing the gun, the piston could be suddenly thru-st forward to the end of the cylinder at a rate commensurate with the rate of discharge of the air, it will be apparent that the pressure of the air during discharge may be maintained above a practical minimum value, or in other words, the pressure may be precluded from decaying to any substantial extent during which split second period when the air is performing its function in the discharging of the shot.

I am enabled to accomplish such a sudden thrust of the piston, by bowing the piston rod n somewhat, thereby effectively turning it into a very stift' and powerful spring. It is preferably so designed that at the end of the 4compression stroke of the piston 1|, the piston rod, under the pressure of which it has been exposed, will have been shortened byan amount comparable to the narrow spacing remaining between the piston and the end of the cylinder. Under these conditions, upon release of the air, the sudden restoration of the piston rod to its normal length will produce a sudden forward thrust of the piston as indicated in Figure 7, to accomplish the result desired.

To derive the most beneficial advantage from this feature, the valve chamber 35 is made onlylarge enough to comfortably accommodate the valve 39 and permit of its being lifted from its sudden and at considerably increasedvelocity.'

It thereby also effectively increases the beneficial results attributable to the follow-up feature of the bowed piston rod. This restrainer may taker.

the form of a hollow plug |0| having a reduced open end threaded through the wall of the-gun barrel, at approximately the firing position of a 5 shot in the barrel. In the hollow of the plug, I provide a spring pressed pin |03 having a rounded end |05 extending but slightly into the bore of the barrel, but sufficiently to preclude free discharge of a shot placed at lthe firing position. The rounded end presents a sloping surface to the shot, thus enabling the pin to be depressed laterally in response to pressure applied normal to the pin axis, and` such pressure will be developed upon opening of the valve to release the air in the cylinder.

I prefer to make this restraining device adjustable, whereby a certain amount of controlA may be exercised asfto the velocity to be obtained. To this end, I provide a hole |01 in the end wall of the plug, through which an adjusting screw |09 may be passed and threaded into the v stem ofthe pin |03. The adjusting screw will thereby enable one to adjust the extent to which the pin protrudes into the bore of the barrel and thereby eectively alter the resistance which must be overcome by the shot before being released.

In completing the pistol, the breech end thereof is enclosed in a casing This casing extends over the grooved portion 2| of the gun bar-l rel, cooperating therewith to form a magazine for holding the pellets in the groove provided therein, and to the rear of the magazine, the casing carries a rear sight H3.

From the description of my improved gun, it will be apparent that the same is capable of fulfilling all the objects of my invention as previously set forth, and while I have disclosed the same in detail in a preferred embodiment thereof, my invention is susceptible to change and modiflcation, without departing from the scope of the same, and I accordingly do not desire to be limited in my protection to the details of my disclosure, except as may be necessitated by the appended claims.

1.A lcompressed air gunA vcomprising a fbarreL -apump associated therewith including ac'ylinder hav-ing'f an' openv end land-supported adj acent said barrel Withl-its'clo'sed end toward the breech end ofthegun, a lever pivoted adjacent the muzzle endfof said barrel, said lever in'oneY extreme' position of swing having av'portion disposed substantilaiil-ly` parallel to said barrel and an angularlir disposed portion extending `across the 'open end of-said-cy1inder, apiston in said cylinder having its working surface facing the closedvend of'v said cylinder, -a-piston vro'dfconn'ected at one end 'to saidpistonfandat its other end to an intermediate pointfon said`lever lying `just slightly beyond 'a line yjoining the pivot axis/of said lever andthe piston-rod connection to said piston, in the direc tion 'l of s'a-id barrel, When's'aidpiston is "at vvthe endfofits compression stroke, va'slidable breech pin normally held at the firing position of a'shot infsaid`-barrel, and adapted to loe-Withdrawn sufcieiitly Vto A'expose the interior'of said barrel 'to a` '-fed opening, and vmeans vconnected to said breech-'pin and extending between the 'open end ofr'said 'cylinder and said lever, injthepath 'of movement of said piston on its intake stroke for effecting-such withdrawal Yoi the breech-pin .to automatically loadsaid gundu'ring the operation of said pump. y

`2."Inan air gun, a gun lbarrel having a feed opening therein for the entranceof a shot into said barrelJ for "subsequent: placementat the firing' position in'fsai'dv barrel ahead of said 'feed opening, albreech pin s'lidable in 'said barrelymeas normally urging said breech pinto s'aidring. po-v sitio'nfa pump associated with saidjgun, and in-- cludin'g'za pump Cylinder and azpiston therein, and means `acted upon by said pump pistoniortein-y poiajrily retractin'g said breeeh pin suiciently to expose-saidbarrel to's'ai'd feedbp'ening '3. :In an air gun, a gun barrel having a feed opening therein for the entrance of a shot'into saidbarrel for subsequent placement lat the vring position in said 'barrel ahead of vsaid feed opening, a breech pin slidable in said barrel" and iieienfirwtefz expo-iesai-(i` ieee "opening-V and-nimm 4. In an air gun, a"gunlbarrelihavinga'ieed" opening" therein-rior? the Lentrance"of :a rshot Vinto said barrel"forsbsequent'fplacernent at the ring position insa-iu barrel 'ahead vor said @feed at the' termi-iiatior'i'--4 f *':anfiritake stroke-of 'sai'df pump for-ivitiidraiwing'fsaid"breech-pinsumeicntiy to*exp'osesaidfeedfopening and admitarshotiinto i said barrel.

opening!! thereiniforf-tiie-entraneef of ai shot into saidbarrel-fiore'sub'seqiient; placenientatv the-ffii"-v f ing position in Sidfbai'rl alie-:35dv 'of fs'aidfeed' opening, a breech pin slidable in said barrel 'and' having l'en .end i protruding f therefrom, Ja :spring pressed lever enga/ging -tsaid protruding fend and normally uz'igingvfsaid'breechlpin to said ring'p'o'4 sitien,v a single ystrokerpurrip'associatedwith said gu-n,-and including an open-end*p'ur'npy cylinder and aipistonf thereinsa-id piston*being` adaptedto' beY partially W'ith'"d'ravvr'ifrrritliefopeni end4 of said cylinder-- at 'the erid' off the' intake Y'stroke thereof, andl arslidablellink 'connected atone--end toI said movement of said pistons. u

,fREFERENoEsfoITEn friiexfouowine references. are df Vrecom' infinie fue oftnisipatenc:

UinmEDfs'r-ATES :PATENTS 

